Andy Murray has insisted he is up for the fight of staying world No.1 as he turns 30 on Monday.

The Scot admitted he was “concerned” about his form after losing to Borna Coric in the fourth round at the Madrid Open in a season where he has struggled form and fitness.

He has a final claycourt warm-up event before the French Open as he defends his title at the Rome Masters this week and he could face local favourite Fabio Fognini in his first match on Tuesday.

But the best player the world said he has the drive to stay on top of the game as he enters his fourth decade.

Murray gives a thumbs up to his coaching staff during the defeat to Borna Coric (Image: Getty Images)

Andy Murray was his last warm-up event before the French Open this week (Image: Getty Images)

“I think I’ve got a good few years left in me,” said the Wimbledon champion. “Physically, this year’s been a little bit of a struggle but at the end of last year, I was absolutely fine, so I’m hoping that when I turn 30 it’s not the end or I am getting like I am on the downward slope now.

“But the best way to test that stuff, I can test it in the gym, is great, all of my training sessions are good, but then it’s about winning matches on the court.

“I will stay at the top only if I win matches so the aim is to lose as little as possible. It will be a fight but I like to fight.

Andy Murray has struggled for form in the early season (Image: Getty)

“I need to maintain my motivation and my standards. It’s certainly going to get tougher to stay right at the top because the younger guys are obviously going to get better and it’s not easy to improve as you get older but you can still do a lot with experience.”

With Roland-Garros starting on Sunday May 28, Murray plans to reunite with head coach Ivan Lendl in London the week before.

“Ivan will be in London on London on May 21 – the day of the Rome final – but I hope to see him only on the Monday!” he said. “We will be togethr for five weeks to prepare better for Paris and Wimbledon.”